Re: Can this program be improved?

From	Bart <bc@freeuk.com>
Newsgroups	comp.lang.c
Subject	Re: Can this program be improved?
Date	2021-12-31 23:59 +0000
Organization	A noiseless patient Spider
Message-ID	<sqo5gl$tbl$1@dont-email.me> (permalink)
References	(6 earlier) <87o84z2bsi.fsf@nosuchdomain.example.com> <sqj0mf$532$1@dont-email.me> <sqkphm$p3g$1@gioia.aioe.org> <sqlpcn$3fa$1@dont-email.me> <sqo2re$fdi$1@dont-email.me>

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On 31/12/2021 23:13, James Kuyper wrote:
> On 12/31/2021 3:20 AM, Bart wrote:
> ...
>> It also doesn't magically solve all issues. You'd have problems with
>> exactly representing 1/3 of 1% for example, or 1/3 of £1 (approx 33.33p
>> or exactly 6/8d in old money), or doing any similar kind of division.
> 
> The issue is not about accurately representing the results of all
> possible divisions. It's about getting the legally mandated results.
> Whenever money is involved, there's people trying to use every possible
> trick to get more of it than they're actually entitled to. As a result,
> regulatory agencies have gotten heavily involved in such issues,
> specifying precisely how financial calculations should be performed.
> I've heard from second-hand sources what kinds of requirements those
> agencies have imposed, but I have not been able to locate any first-hand
> sources. It hardly matters, because the detailed requirements vary from
> one country to another, and even between different industries. However,
> they all are based upon the same idea:
> 
> Every quantity you need to calculate must, in effect, be stored as an
> integer with a scaling factor that is an integer power of 10, usually
> negative. All calculations are performed as if using ordinary integer
> arithmetic, with the appropriate scaling factor for the result. I say
> "in effect", because on some platforms you can achieve the same result
> by relying upon hardware support for decimal floating point.
> 
> The point is, if you don't use either scaled integers or decimal
> floating point or something similar, you won't always round the results
> of your calculation the same way as is required by the relevant
> regulations.  Even if it only happens rarely and only involves a tiny
> amount of money, if the regulators find out they will come after you
> because the fact that you calculated it incorrectly is taken as evidence
> hinting that you were at least sloppy with your calculations, and at
> worst, may have been trying to do something fraudulent.

Then the regulators should themselves provide a library that performs 
arithmetic or other calculations according to their standards.

That's if someone is working on software where this is an actual necessity.

I'm just fed up with people always bringing this up on forums when some 
quantity might involve money. Those advanced requirements are heavily 
dependent on application areas, and little to do with basic programming, 
especially when a language doesn't provide the special types (scaled 
integers etc) that might be needed.

Thread

Can this program be improved? Manu Raju <MR@invalid.invalid> - 2021-12-25 01:00 +0000
  Re: Can this program be improved? Andrey Tarasevich <andreytarasevich@hotmail.com> - 2021-12-24 21:44 -0800
    Re: Can this program be improved? David Brown <david.brown@hesbynett.no> - 2021-12-25 12:56 +0100
    Re: Can this program be improved? Tim Rentsch <tr.17687@z991.linuxsc.com> - 2021-12-25 11:13 -0800
    Re: Can this program be improved? Manfred <noname@add.invalid> - 2021-12-25 23:50 +0100
    Re: Can this program be improved? Manu Raju <MR@invalid.invalid> - 2021-12-26 18:52 +0000
      Re: Can this program be improved? Lew Pitcher <lew.pitcher@digitalfreehold.ca> - 2021-12-26 19:22 +0000
        Re: Can this program be improved? Manu Raju <MR@invalid.invalid> - 2021-12-26 21:30 +0000
          Re: Can this program be improved? Bart <bc@freeuk.com> - 2021-12-26 22:02 +0000
          Re: Can this program be improved? Richard Damon <Richard@Damon-Family.org> - 2021-12-26 18:24 -0500
          Re: Can this program be improved? Lew Pitcher <lew.pitcher@digitalfreehold.ca> - 2021-12-27 00:47 +0000
    Re: Can this program be improved? Guillaume <message@bottle.org> - 2021-12-29 17:52 +0100
      Re: Can this program be improved? Bart <bc@freeuk.com> - 2021-12-29 17:49 +0000
        Re: Can this program be improved? Andrey Tarasevich <andreytarasevich@hotmail.com> - 2021-12-29 11:33 -0800
          Re: Can this program be improved? James Kuyper <jameskuyper@alumni.caltech.edu> - 2021-12-29 22:45 -0500
            Re: Can this program be improved? Andrey Tarasevich <andreytarasevich@hotmail.com> - 2021-12-30 00:35 -0800
              Re: Can this program be improved? David Brown <david.brown@hesbynett.no> - 2021-12-30 10:19 +0100
          Re: Can this program be improved? Bart <bc@freeuk.com> - 2022-01-01 18:19 +0000
            Re: Can this program be improved? Bart <bc@freeuk.com> - 2022-01-01 19:33 +0000
        Re: Can this program be improved? Keith Thompson <Keith.S.Thompson+u@gmail.com> - 2021-12-29 14:37 -0800
          Re: Can this program be improved? Bart <bc@freeuk.com> - 2021-12-29 23:09 +0000
            Re: Can this program be improved? scott@slp53.sl.home (Scott Lurndal) - 2021-12-29 23:54 +0000
              Re: Can this program be improved? Keith Thompson <Keith.S.Thompson+u@gmail.com> - 2021-12-29 16:11 -0800
              Re: Can this program be improved? Kaz Kylheku <480-992-1380@kylheku.com> - 2021-12-30 00:34 +0000
                Re: Can this program be improved? Bart <bc@freeuk.com> - 2021-12-30 12:49 +0000
                Re: Can this program be improved? Kaz Kylheku <480-992-1380@kylheku.com> - 2021-12-30 21:04 +0000
                Re: Can this program be improved? Bart <bc@freeuk.com> - 2021-12-31 02:13 +0000
            Re: Can this program be improved? Keith Thompson <Keith.S.Thompson+u@gmail.com> - 2021-12-29 16:09 -0800
              Re: Can this program be improved? Kaz Kylheku <480-992-1380@kylheku.com> - 2021-12-30 00:59 +0000
                Re: Can this program be improved? Keith Thompson <Keith.S.Thompson+u@gmail.com> - 2021-12-29 17:48 -0800
                Re: Can this program be improved? Kaz Kylheku <480-992-1380@kylheku.com> - 2021-12-30 20:47 +0000
              Re: Can this program be improved? Bart <bc@freeuk.com> - 2021-12-30 01:06 +0000
                Re: Can this program be improved? Malcolm McLean <malcolm.arthur.mclean@gmail.com> - 2021-12-30 04:48 -0800
                Re: Can this program be improved? Manfred <noname@add.invalid> - 2021-12-30 18:16 +0100
                Re: Can this program be improved? Bart <bc@freeuk.com> - 2021-12-31 02:20 +0000
                Re: Can this program be improved? Manfred <noname@add.invalid> - 2021-12-31 18:25 +0100
                Re: Can this program be improved? James Kuyper <jameskuyper@alumni.caltech.edu> - 2021-12-31 18:13 -0500
                Re: Can this program be improved? Bart <bc@freeuk.com> - 2021-12-31 23:59 +0000
                Re: Can this program be improved? "james...@alumni.caltech.edu" <jameskuyper@alumni.caltech.edu> - 2021-12-31 16:20 -0800
                Re: Can this program be improved? Keith Thompson <Keith.S.Thompson+u@gmail.com> - 2021-12-31 16:35 -0800
                Re: Can this program be improved? Bart <bc@freeuk.com> - 2022-01-01 00:53 +0000
                Re: Can this program be improved? Keith Thompson <Keith.S.Thompson+u@gmail.com> - 2021-12-31 20:22 -0800
                Re: Can this program be improved? Malcolm McLean <malcolm.arthur.mclean@gmail.com> - 2021-12-31 22:04 -0800
                Re: Can this program be improved? Keith Thompson <Keith.S.Thompson+u@gmail.com> - 2022-01-01 14:59 -0800
                Re: Can this program be improved? Malcolm McLean <malcolm.arthur.mclean@gmail.com> - 2022-01-02 17:22 -0800
                Re: Can this program be improved? Keith Thompson <Keith.S.Thompson+u@gmail.com> - 2022-01-02 20:49 -0800
                Re: Can this program be improved? Malcolm McLean <malcolm.arthur.mclean@gmail.com> - 2022-01-03 03:09 -0800
                Re: Can this program be improved? scott@slp53.sl.home (Scott Lurndal) - 2022-01-03 16:22 +0000
                Re: Can this program be improved? Keith Thompson <Keith.S.Thompson+u@gmail.com> - 2022-01-03 14:42 -0800
                Re: Can this program be improved? Malcolm McLean <malcolm.arthur.mclean@gmail.com> - 2022-01-03 14:52 -0800
                Re: Can this program be improved? gazelle@shell.xmission.com (Kenny McCormack) - 2022-01-03 22:58 +0000
                Re: Can this program be improved? Malcolm McLean <malcolm.arthur.mclean@gmail.com> - 2022-01-04 04:27 -0800
                Re: Can this program be improved? gazelle@shell.xmission.com (Kenny McCormack) - 2022-01-04 13:39 +0000
                Re: Can this program be improved? David Brown <david.brown@hesbynett.no> - 2022-01-04 00:18 +0100
                Re: Can this program be improved? Keith Thompson <Keith.S.Thompson+u@gmail.com> - 2022-01-03 15:24 -0800
                Re: Can this program be improved? Malcolm McLean <malcolm.arthur.mclean@gmail.com> - 2022-01-03 15:43 -0800
                Re: Can this program be improved? Öö Tiib <ootiib@hot.ee> - 2022-01-03 21:19 -0800
                Re: Can this program be improved? Mateusz Viste <mateusz@xyz.invalid> - 2022-01-04 09:23 +0100
                Re: Can this program be improved? Guillaume <message@bottle.org> - 2022-01-04 18:18 +0100
                Re: Can this program be improved? Malcolm McLean <malcolm.arthur.mclean@gmail.com> - 2022-01-04 10:35 -0800
                Re: Can this program be improved? Keith Thompson <Keith.S.Thompson+u@gmail.com> - 2022-01-04 14:07 -0800
                Re: Can this program be improved? Malcolm McLean <malcolm.arthur.mclean@gmail.com> - 2022-01-04 15:11 -0800
                Re: Can this program be improved? Keith Thompson <Keith.S.Thompson+u@gmail.com> - 2022-01-04 15:47 -0800
                Re: Can this program be improved? Malcolm McLean <malcolm.arthur.mclean@gmail.com> - 2022-01-04 18:30 -0800
                Re: Can this program be improved? scott@slp53.sl.home (Scott Lurndal) - 2022-01-04 23:46 +0000
                Re: Can this program be improved? Bart <bc@freeuk.com> - 2022-01-04 18:41 +0000
                Re: Can this program be improved? Malcolm McLean <malcolm.arthur.mclean@gmail.com> - 2022-01-04 10:52 -0800
                Re: Can this program be improved? scott@slp53.sl.home (Scott Lurndal) - 2022-01-04 19:00 +0000
                Re: Can this program be improved? Malcolm McLean <malcolm.arthur.mclean@gmail.com> - 2022-01-04 11:15 -0800
                Re: Can this program be improved? Guillaume <message@bottle.org> - 2022-01-04 21:57 +0100
                Re: Can this program be improved? Bart <bc@freeuk.com> - 2022-01-04 21:02 +0000
                Re: Can this program be improved? scott@slp53.sl.home (Scott Lurndal) - 2022-01-04 21:38 +0000
                Re: Can this program be improved? Manfred <noname@add.invalid> - 2022-01-04 23:01 +0100
                Re: Can this program be improved? David Brown <david.brown@hesbynett.no> - 2022-01-04 09:31 +0100
                Re: Can this program be improved? Malcolm McLean <malcolm.arthur.mclean@gmail.com> - 2022-01-04 01:30 -0800
                Re: Can this program be improved? David Brown <david.brown@hesbynett.no> - 2022-01-04 14:55 +0100
                Re: Can this program be improved? Malcolm McLean <malcolm.arthur.mclean@gmail.com> - 2022-01-04 06:21 -0800
                Re: Can this program be improved? David Brown <david.brown@hesbynett.no> - 2022-01-04 16:49 +0100
                Re: Can this program be improved? gazelle@shell.xmission.com (Kenny McCormack) - 2022-01-04 15:56 +0000
                Re: Can this program be improved? gazelle@shell.xmission.com (Kenny McCormack) - 2022-01-04 15:03 +0000
                Re: Can this program be improved? gazelle@shell.xmission.com (Kenny McCormack) - 2022-01-03 22:54 +0000
                Re: Can this program be improved? Mateusz Viste <mateusz@xyz.invalid> - 2022-01-03 09:22 +0100
                Re: Can this program be improved? Malcolm McLean <malcolm.arthur.mclean@gmail.com> - 2022-01-03 03:30 -0800
                Re: Can this program be improved? David Brown <david.brown@hesbynett.no> - 2022-01-03 17:22 +0100
                Re: Can this program be improved? Malcolm McLean <malcolm.arthur.mclean@gmail.com> - 2022-01-03 08:48 -0800
                Re: Can this program be improved? Mateusz Viste <mateusz@xyz.invalid> - 2022-01-03 18:42 +0100
                Re: Can this program be improved? Bart <bc@freeuk.com> - 2022-01-03 17:59 +0000
                Re: Can this program be improved? Malcolm McLean <malcolm.arthur.mclean@gmail.com> - 2022-01-03 11:09 -0800
                Re: Can this program be improved? Mateusz Viste <mateusz@xyz.invalid> - 2022-01-03 20:32 +0100
                Re: Can this program be improved? Malcolm McLean <malcolm.arthur.mclean@gmail.com> - 2022-01-03 11:58 -0800
                Re: Can this program be improved? scott@slp53.sl.home (Scott Lurndal) - 2022-01-03 18:13 +0000
                Re: Can this program be improved? gazelle@shell.xmission.com (Kenny McCormack) - 2022-01-03 20:05 +0000
                Re: Can this program be improved? Bart <bc@freeuk.com> - 2022-01-01 16:53 +0000
          Re: Can this program be improved? Kaz Kylheku <480-992-1380@kylheku.com> - 2021-12-30 00:29 +0000
  Re: Can this program be improved? Bart <bc@freeuk.com> - 2021-12-25 12:47 +0000
    Re: Can this program be improved? Manu Raju <MR@invalid.invalid> - 2021-12-26 18:56 +0000
  Re: Can this program be improved? Lew Pitcher <lew.pitcher@digitalfreehold.ca> - 2021-12-25 17:38 +0000
    Re: Can this program be improved? Öö Tiib <ootiib@hot.ee> - 2021-12-25 10:58 -0800
      Re: Can this program be improved? Lew Pitcher <lew.pitcher@digitalfreehold.ca> - 2021-12-25 19:16 +0000
        Re: Can this program be improved? Öö Tiib <ootiib@hot.ee> - 2021-12-25 11:25 -0800
      Re: Can this program be improved? "Chris M. Thomasson" <chris.m.thomasson.1@gmail.com> - 2021-12-25 15:01 -0800
        Re: Can this program be improved? Lew Pitcher <lew.pitcher@digitalfreehold.ca> - 2021-12-25 23:09 +0000
          Re: Can this program be improved? "Chris M. Thomasson" <chris.m.thomasson.1@gmail.com> - 2021-12-25 20:56 -0800
    Re: Can this program be improved? scott@slp53.sl.home (Scott Lurndal) - 2021-12-25 19:30 +0000
      Re: Can this program be improved? Keith Thompson <Keith.S.Thompson+u@gmail.com> - 2021-12-25 15:50 -0800
        Re: Can this program be improved? Manu Raju <MR@invalid.invalid> - 2021-12-26 19:02 +0000
    Re: Can this program be improved? Andrey Tarasevich <andreytarasevich@hotmail.com> - 2021-12-25 11:53 -0800
    Re: Can this program be improved? Manu Raju <MR@invalid.invalid> - 2021-12-26 19:00 +0000
  Re: Can this program be improved? Tim Rentsch <tr.17687@z991.linuxsc.com> - 2021-12-25 11:22 -0800
    Re: Can this program be improved? Manu Raju <MR@invalid.invalid> - 2021-12-26 19:01 +0000
  Re: Can this program be improved? Malcolm McLean <malcolm.arthur.mclean@gmail.com> - 2021-12-25 13:27 -0800
    Re: Can this program be improved? Andrey Tarasevich <andreytarasevich@hotmail.com> - 2021-12-25 16:06 -0800
  Re: Can this program be improved? Lew Pitcher <lew.pitcher@digitalfreehold.ca> - 2021-12-29 15:21 +0000

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